The present invention generally relates to endoscopic instruments, and more particularly to biopsy forceps and other endoscopic end effectors.
Endoscopic biopsy forceps are a medical instrument used in combination with an endoscope for removing tissue samples from inside a patient's body for analysis. These instruments typically include an elongate flexible member having a biopsy jaw assembly mounted on one end. The jaw assembly includes a clevis holding pivotally mounted jaws adapted for removing tissue for analysis. An actuator comprising an actuator handle and an actuator member extending from the handle to the pivoting jaws of the jaw assembly moves the jaws between an open position in which the ends of the jaws are spaced and a closed position in which the ends of the jaws contact each other to obtain the tissue sample. In addition to biopsy forceps, some aspects of the present invention relate to other types of endoscopic end effectors such as a flexible grasper, a dissector, or scissors.
Biopsy forceps frequently have teeth along the mating edges of the jaws to improve grasping of the tissue. As will be appreciated by those skilled in the art, the teeth extending along each side of the jaw and those extending across the end of the jaw interact differently with the tissue. In the past, these differences in interaction have not been taken into account when selecting tooth profiles for the different portions of the jaw. A fundamental function of biopsy forceps is to pinch tissue in order to tear a sample free. The teeth, particularly those at the end of the jaw, are believed to have a significant impact on sample depth and weight.
Many conventional jaws have been made so that each jaw in the assembly has a different configuration. When a single jaw assembly uses two different jaw configurations, the different jaws must be manufactured, stored and handled during assembly. This situation results in manufacturing inefficiency and a cost increase. In addition, many conventional jaws are cast or molded. Jaws designed to be manufactured using other less expensive processes have the potential for reducing overall assembly cost.
Because the jaw assembly includes a clevis, certain obstacles are presented during assembly. If the clevis and axle pin are inseparably assembled before the jaws are installed, the arms of the clevis must be spread when the jaws  are being assembled with the clevis. If the clevis and axle pin are separate, the jaws must be inserted between the clevis arms and aligned with the axle pin. Either process has a potential for increasing assembly cost. Still further, connecting the actuator members to the jaw assembly is difficult to achieve using conventional devises because the clevis blocks clear access to these components.
Once assembled, the jaw assembly has portions (e.g., distal portions) that are susceptible to higher stresses and wear. In order to optimize the jaw, some portions of the jaw can be thicker or made from different materials. Although producing a jaw cup by stamping has economic advantages, conventional jaw assemblies have been unable to take advantage of a stamped jaw cup while having thicker portions or portions made from different materials.
During use, a large jaw size is desired to obtain a large tissue sample. However, when the forceps are being pushed into position, a small jaw size is desirable so that the forceps can travel through smaller radius turns. Using conventional jaw shapes, the jaw size is limited by turning radius.
Among the problems common to known biopsy forceps and end effectors generally is that these instruments are very long and flexible, making packaging, storage and handling difficult. The instruments are frequently coiled when packaged. When the packaging is opened, the instruments can spontaneously uncoil, become unmanageable, potentially falling on the floor, and becoming contaminated or being damaged. Thus, there is a need for a feature that retains these types of instruments in a coiled configuration when unpackaged.